Microstructure Evolution in High Purity Aluminum Single Crystal Processed by Equal Channel Angular Pressing (ECAP)

Jinfang Dong; Qing Dong; Yongbing Dai; Hui Xing; Yanfeng Han; Jianbo Ma; Jiao Zhang; Jun Wang; Baode Sun

doi:10.3390/ma10010087

Microstructure Evolution in High Purity Aluminum Single Crystal Processed by Equal Channel Angular Pressing (ECAP)

Materials (Basel). 2017 Jan 22;10(1):87. doi: 10.3390/ma10010087.

Authors

Jinfang Dong¹, Qing Dong², Yongbing Dai³, Hui Xing⁴, Yanfeng Han⁵, Jianbo Ma⁶, Jiao Zhang⁷, Jun Wang⁸, Baode Sun⁹

Affiliations

¹ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. jfangdong@hotmail.com.
² Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. dongqing19@163.com.
³ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. ybdai@sjtu.edu.cn.
⁴ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. xinghui@sjtu.edu.cn.
⁵ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. yfhan@sjtu.edu.cn.
⁶ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. kaixnjb@sjtu.edu.cn.
⁷ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. zj119@sjtu.edu.cn.
⁸ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. junwang@sjtu.edu.cn.
⁹ Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. bdsun@sjtu.edu.cn.

Abstract

Aluminum single crystal with 99.999% purity was deformed at room temperature by equal channel angular pressing (ECAP) up to 16 passes. Grain size and misorientation of processed samples were quantitatively characterized by TEM and EBSD. The results show that the refinement efficiency of high purity aluminum single crystal was poor in the initial stage. Extrusion by fewer ECAP passes (n ≤ 8) resulted in only elongated grains containing a large number of subgrains and small misorientations between grains. Stable microstructures of nearly equiaxed grains with high misorientations were obtained by 15 passages, indicating that the initial extremely coarse grains and highly uniform grain orientation are not conducive to the accumulation of strain energy. The initial state of high purity aluminum has a significant effect on the refining efficiency of the ECAP process.

Keywords: deformation; equal channel angular pressing (ECAP); grain boundary; high purity aluminum; single crystal.